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FAQs about Acroporid Coral Behavior

Related Articles: Acroporids, SPS Corals

Related FAQs: Acroporids 1, Acroporids 2, Acroporid Identification, Acroporid Selection, Acroporid Compatibility, Acroporid Feeding, Acroporid Disease, Acroporid Systems, Acroporid Reproduction, Stony/True Coral, Coral System Set-Up, Coral System Lighting, Stony Coral Identification, Stony Coral Selection, Coral PlacementFoods/Feeding/Nutrition, Disease/Health, Propagation, Growing Reef CoralsStony Coral Behavior,

"When in doubt, do nothing"

Acropora questions. 6/5/08
Hello!
<Greetings!>
I think I have an Acropora Digitata.
<Looks like a Montipora digitata to me...>
Bought the little guy from LiveAquaria.com about 2 months ago.
He used to be in a smaller tank, didn't grow much, and stayed brown. I have recently put him in my bigger tank with the same amount of light, and more flow, and he is turning into the purple color you can see in the picture.
<Does happen. Always exciting.>
I noticed in the FAQs that it is simply just utilizing the light in a different way, hence the color change. Correct?
<In essence. Better/more light makes a need for UV-blocking pigments, and better water flow/ quality allows for coloring pigments to be produced.>
Also! The tips on the ends of the "branches," seem to be a creamy, off white. Is that a sign of growth, or is it stunted from being put into a new tank? It has been in the tank a little over 3 weeks..
<Just the growing tips, as far as I can tell. If you don't see shrinking tissue and there is continued growth, all is well.>
Thanks!
<No troubles. Benjamin>

Acropora questions. Sys.  6/5/08
Hello!
<Nicolas>
I think I have an Acropora digitata. Bought the little guy from LiveAquaria.com about 2 months ago.
He used to be in a smaller tank, didn't grow much, and stayed brown. I have recently put him in my bigger tank with the same amount of light, and more flow, and he is turning into the purple color you can see in the picture. I noticed in the FAQs that it is simply just
utilizing the light in a different way, hence the color change. Correct?
<Possibly. Could be other influences, differences in the two settings as well>
Also! The tips on the ends of the "branches," seem to be a creamy, off white. Is that a sign of growth, or is it stunted from being put into a new tank?
<Let's hope the former. Often the growing ends/tips of Acroporas are light/er colored>
It has been in the tank a little over 3 weeks..
Thanks!
<Keep enjoying, reading... Bob Fenner>

Acropora millepora retract  4/29/08
Hi Crew:
<Rich>
As usual thanks for the great wealth of information. My tank is a mixed reef with various Acropora placed middle to high in the tank and some Zoanthids and LPSs on the bottom. Tank parameters are Alk 9, calcium 420, magnesium 1350, salinity 1.024. Tank is 125 gallons with sump and refugium.
Lighting 2x250 mh, phoenix bulbs, 2x 54 t5's actinic. Flow is provided by 2 Vortech pumps. I have a GEO calcium reactor and ATI skimmer which seem to be doing their job. Other pieces of equipment are a Phosban reactor
<... Acropora need soluble HPO4...>
and UV sterilizer. Finally to the question. Amongst my various types of Acropora are 3 pieces of Acropora millepora placed in various spots of the tank.
The corals took a few months to acclimate, but then started to grow nicely.
The hairy polyps had great extension and the colors were alarming.
<Good word>
Now, all of the hairy extensions have retracted. The corals still have their color and I can see polyp extension at night but only on the tips of the coral, not the hairy polyps seen during the day. My other types of Acropora have not skipped a beat with regard to growth. I've been monitoring this situation for the last week, hoping the hairy polyps would return with no success. Is this natural behavior?
<I do think so, yes... Most Acroporids do "feed", open their polyps mainly during dark periods... when their preferred sizes, types of zooplankter foods are out and about...>
I'm assuming it isn't. If not, do you
have any words of wisdom? Thanks again for your time and knowledge.
Rich
<I'd be testing for phosphate... leaving some... Bob Fenner>

Re: Acropora millepora retract 4/29/08
Mr. Fenner:
Thank you for the quick reply. I will shut down the phosphate reactor and
monitor.
Rich
<Ah, very good. I would take a look/see during the night... to observe whether this colony is open then. Cheers, B>

Monticap, not Monty Hall  - 03/12/07
Dear Sir,
<Ernest>
I am just starting on having an SPS dominated tank in my 120gallon reef tank. 48 inch length x 30 inch high x 20 inch wide.
<Okay>
The tank has been set up for about 3 months with initial growth of coralline algae showing up. (I believe its good news).
<Yes... generally indicative of full-cycling, suitable habitat...>
Tank parameters are on par.
<Fore!>
And I have just purchased a monticap (very small ~ 2 inch wide). Which has been in my tank for 3 days now.
<For others... this is some sort of new-reef-speak for a species of Acroporid, Montipora capricornis>
My lighting is 400W 12000K Metal Halide, I've placed my monticap halfway up the tank so around 20 inch into the water.
My question would be, for SPS and this monticap, how deep would I be able to place them in the water before its not good for them? MH height is 20 inch from water.
<Mmm, really depends on what species, and more importantly, what conditions they were living under recently (and to a lesser extent what conditions from some time back...). In practical terms, better to start most deeper... raise up to shallower in weeks time... to prevent "burning"/bleaching, stress>
I have a Tunze WaveBox for flow, would adding Tunze stream 6100 be better or 6200 ?
<Mmm, the more the merrier in the way of flow>
Also after 3 days I do not see much polyp extension on the monticap, would this be a cause for concern?
<Mmm, nope... too short a period of time as yet to have become acclimated... and don't have much in the way of polyp extension at any length...>
There was some slight damage on it when I first got it, i.e. some small broken tissue, but it was a cheap pieces so I bought it.
Further I am planning on introducing grape Caulerpa into the sump as a natural filtration media, would that be advised?
<Mmm, no... best to look around for other genera, even Division (Reds, Rhodophytes)...>
There's no Chaeto in Hong Kong (where I live).
Best Regards,
Ernest
<Mmm, please read here: http://www.wetwebmedia.com/marine/inverts/index.htm
The tray with Stony Corals... Scleractinians... Bob Fenner>

Crazy Coral Color Issue  12/12/06
Good Afternoon Guys & Gals:
<Scott F. your guy tonight>
I have a quick one for you. I recently obtained a small (1") green Acropora frag. The odd thing is that half of the frag seems to have lost it's neon colour. I do not think the tissue is gone as it does not appear any different to the coloured side except it is not brightly coloured on that side. I just wanted to ask if you have encountered this before and if you think the frag is just adjusting to the change in lighting..
<I have personally encountered such a phenomenon before, and I am not exactly certain what contributed to it. I speculate that it's something to do with lighting; one side lit well, and perhaps the other side not well at all.>
It came from 2x250w halide bulbs.
I have 2x150 HQI 10K bulbs that are basically brand new.
water params
temp: 79-80
ph: 8.2
nitrite: 0
nitrate: 0
ammonia: 0
calcium: 500mg/L
alkalinity: 4meq/L
Flow: ~24x turnover
Regards, J
<Well, J, your environmental parameters sounds fine. I suspect that it may correct itself once the frag adapts to your lighting. In the absence of tissue recession, etc., I'd recommend staying patient and waiting it out. Regards, Scott F.>
 
Purple Spots on Acropora yongei  3/10/06
Hello. One of my corals (I think it is A. yongei) has been developing a number of small, purple spots. It does not look like the tissue is sloughing off in these areas, but I can't see any polyp extension either. This coral has been in my tank and doing okay for over 2 years. I did change from 175W to 250W MH, but that was over 6 months ago and this symptom just started to show up about a month ago and is progressing slowly. There does not seem to be a pattern, high or low on the coral. All other SPS and LPS species in the tank, including other Acropora, look normal and are doing fine. Water parameters are good. Please see attached. Thanks.
<A very nice pic of a very nice specimen. I do believe this is "just" coloration returning to the colony... Beautiful. Bob Fenner>

Acropora turning brown  
Bob: Love your site. <Adam here today.  Thanks for the kind words.>
My questions is as follows. I purchased some Acro's that had different colors. My 125gal. nitrates and phosphates jumped over the recommended limits and the across turned brown. Now my tank is reading almost 0% phosphates and nitrates and my across are growing quite well and the tips are gaining color. I worked diligently to get my nitrates and phosphates under control. My question is as follows, will the brown part of the across eventually turn to their original colors or will they remain forever brown. Thanks, Joey
<Ahhh... an easy question!  I don't know.  There are many variables that effect Acro coloration.  Nutrients, alkalinity, lighting intensity, lighting spectrum, iron, feeding, etc., and often it is impossible to predict, let alone closely control all of these variables.  In many cases, wild Acroporas fail to retain or regain their wild coloration.  This is why those that do and do so under a variety of conditions are so prized. Sorry for the "non-answer", but I hope it helps.  AdamC.>

Acropora Color Change
Bob:
<Scott F. in today!>
I purchased some colorful Acroporas and placed them in my tank. In a couple of weeks, they started to turn all brown. I have since got my phosphates to 0% and my nitrates to under 5%. The across are starting to grow with tips being colorful. My question is will the entire Acropora return to its original color now that I have my water quality under control?
Joey
<Great question, Joey. The prevailing wisdom is that the colors of coral are a sort of natural "sunscreen", which the coral will manufacture as it needs them. Under intense light and high water quality, it is certainly possible that the colors will return to something approaching their original splendor. Phosphates are well known to inhibit calcification and color in stony corals, so you were right on in trying to get water quality in order. Interestingly, you will often get different colors for the same species even under different lights. Good luck! Regards, Scott F>

Acropora ahoy!
"What was I thinking?"
"It cost you HOW much!?" 
"Throw it in there and pray!"
"Yeah, that's a nice one."
"HA! goooood luck!"
Well...so far I've had more luck with SPS than with MPS or LPS, so what the heck. The colony (Acropora gemmifera as far as I can tell at the moment) is 3" across and 2" inches high, and NOW I know what an axial corallite looks like. been eyeing it for 2 weeks since it came in. perfect coverage, extension. the retailer didn't even have it under direct lighting. So the adventure starts...
do you think I'm crazy?
Chris 
>>
Not crazy, perhaps just enthusiastic (From the Gk. meaning "the god in you", en thuus, hence the term theology...) Do take a look at the A. gemmifera and other pix I have placed in a survey piece (the "Acroporidae") on the site: www.wetwebmedia.com... More info there re the selection and care of these quintessential SPS'.
Bob Fenner

Re: Acropora ahoy!
uhoh. Went out in the Gulf for Spanish Mackerel and Cobia today. When I got back, my new Acropora (which was very dark burgundy when I got it) abruptly (in less than 12 hours!) had changed is tissue color to a light tan-orange. (1 or 2 branches were still dark), and the polyps were expelling the zooxanthellae w/mucus strands. The axial corallites have not faded however. Did I waste my money (I won't give up on it until its dead or thriving)? Is this even necessarily a bad sign? If it is, is it treatable?
thank you, Chris
(PS, I am extremely stubborn and do not give up on anything, especially corals, so I am definitely an optimist, and don't ever tell me that something can't be done or at least attempted, because I'll stand firm and accomplish it or at least try it, and for the moment, the death of my Faviid polyps has ceased to progress any further after supplying it with augmented circulation) 
>>
Ah, good to hear... not a good change in your Staghorn... but not the end of its or your world...
Bob Fenner

Re: Acropora ahoy!
Though I'm disappointed in the color fading in my Acro, and distressed to hear that its a negative change, the colony really doesn't look any worse for wear this morning (no bleaching, etc.). maybe the color will return eventually.
Chris >>
Yes... the coloring is a "chicken-egg" type of situation... the predominant pigments residing in your Acroporid are a function of what's available (made by its zooxanthellae), chemical, nutrient, physical (circulation, dissolved oxygen, carbon dioxide, alkalinity, light quality/quantity/duration, presence of other bio-chemical agents (from other livestock).... and many other considerations... You can and do easily effect the color... as you will find.
Bob Fenner

Re: Acropora ahoy!
pigments or a "function" of what's available? is that like 
f(p) = x + y + z +...
f(current pigmentation) = x + y + z (sum of phys, chem, and light, etc. variable interactions and effects)?
<Yes, if you'll allow the addition of a couple of qualifying additions (derivatives, chain-rule extensions, exponentials... to some of these variables... Like the Maxwell-Beerman Light Extinction coefficient (e to the minus ir...)>
so by variable manipulation (after acclimation is complete) thezooxanthellae pigmentation (function) will change and develop accordingly? Chris
>>
Or simple time and variability going by...
Bob Fenner

Acropora and Sea Fan questions
Hi all!  Thanks as always for a great site.  
<our pleasure>
I don't know where I'd be without my daily dose of WWM.
<out of the Institution, perhaps?>
My first question is really more just curiosity than a problem (I hope). I've noticed that my Acropora polyps are almost always out during the day.  They close after the lights have been out for a while or after a feeding.
<feeding particulates that is... they prefer nanoplankton and feeding by absorption instead (some). Thus... no need or irritation by the turbidly of plankton at night or your feeding>
I'm puzzled because the Acroporas that I've see in the display tanks at my local pet stores are always closed.  
<varies by species, water quality, water flow, etc>
The pictures I've seen are usually too small to distinguish the polyps.  What is the normal behavior supposed to be?  
<varies>
Do I have anything to worry about?  
<nope>
I've attached a picture so that you can see what my coral typically looks like.  
<a handsome coral>
I hope it's not too big,
<if only I had a dollar for every time I had to say that [fill in your own joke here]>
was the smallest I could make it without losing the detail.
<[follow up joke inserted HERE]>
I feed them a variety of meaty foods that I blend in a hand-held blender until very fine.  
<a nice effort but likely little help. They do not eat phyto... and prepared meaty foods are grossly too large. They need nano-sized zooplankton. A fishless upstream refugium would be a much bigger help>
I feed the tiny suspended food to my small polyped corals
and sea fan,
<yes... better for the sea fan indeed>
and the larger crumbs that settle on the bottom of the bowl I
feed to my sun coral.
<good strategy>
My sun coral, by the way, is doing very well and
growing fast.
<excellent. Do look in archives for the old article in Aquarium Frontiers by Joe Yaiullo on asexual planulation of this coral. Fantastic!>
My second question is about my sea fan.  There is some Cyanobacteria growing on the fan -- but no where else in the tank,
<yes... needs more random turbulent flow here... they have evolved by design to trap particles!>
fortunately.  How can I safely remove it?  
<just better flow bud... tweak your outlets but no laminar action here. Have two effluents converge above it perhaps>
The Cyano is beginning to smother the fan, but otherwise the fan
seems to be doing very well, even growing.  I've included a picture of the fan.  You can see the dark areas where the Cyano is growing. I have a 75 gallon tank with lots of live rock and about 3 inches of live sand.  I keep a protein skimmer and a small carbon filter running all of the time.  My protein skimmer is a Turboflotor 1000 multi.  The cup is filled about once a week (is that enough?).  
<not really... (hence the Cyano). This is a skimmer with a good design that needs pampering and tweaking. There are even companies that sell modified Turboflotors. Browse the archives here and the message boards for modification tips and tricks.>
For lighting, I have a 384 watt PC with two 10000K and two actinic bulbs. My water parameters are:
>pH = 8.3
>dKH = 9.3
>Calcium = ~400
>Ammonia = 0
>Nitrite = 0
>Nitrate = 10
Thanks, Patrick
<best regards, Anthony>

Acropora polyp extension 3/3/03
Hi Gang,
<cheers, bud>
I have a question regarding my Acropora.  I have three different species, some I've had for over three years.  My most recent are the more thicker stem species that look like the Aspera or Tenuis species.  The latest is a really nice tri-color from Walt Smith.  The problem I am looking for help on is the polyps are not extending.  In the store I purchased them from they appear almost fuzzy like due to the polyps.  Mine are smoother due to the retraction.  
<the list of possible influences is daunting... in contrast to your dealer's display: water clarity, age of lamps, color of lamps, direct and total energy of water flow, DOC levels... etc>
The growth rate is good, but I fear that this may not be for long.  
<polyp extension is not correlative to growth rates, bud>
My tank parameters are good. T=75, DKH 10, Calcium a little low 360 (no reactor), Magnesium 1350,
<easy on the Mag with a lower Ca>
and ORP 345.  I change about 10 gallons a week in a 125G tank with 35 gallon refugium on reverse lighting with sea grasses no Caulerpa.  main tank lighting is 3-175 watt MH, and 2 VHO 140 Actinic.  I also have 2-tangs 6", and 5 small fish 3".  I have never seen any fish peck at these corals.  Any ideas??  
<the most common and easiest parameter to tweak is water flow... usually more is better. Adjust or increase the amount this coral gets... avoid laminar, of course. The other thing is that LFS waters tend to be higher in DOC levels, lower in water clarity and light (age of bulbs, salt creep, etc) due to commercial "business" and setting... all of which may force a coral to extend polyps further panning for light and food. It not always a good thing. Extension is good... overextension is bad. Ciao, bub. Anthony>

Heavily sliming Acropora 5/3/04
Hi, could you please tell me which Acropora species slime the most heavily? Thanks
<Yup.  The slimiest one!  Seriously though...  Many Acroporas are copious slimers.  The problem is that despite the fact that so many folks attach species names to their Acroporas, making such an identification is nearly impossible for the average (even advanced) hobbyist.  Comparison to a picture in a book doesn't work.  Even a very detailed analysis of the gross physical characteristics of an Acropora will usually only narrow down the choices.  In many cases, microscopic examination is required.  Sorry for the rant, but as you can tell, this is a pet peeve.  Best Regards, Adam>

Acropora polyp extension 8/19/04
Hi, I'm getting sick and tired of my across polyp extension. when I get an Acro that has long hairy polyps, a couple of weeks after I get them, the polyps are not hairy anymore, and shrink up inside the coral. What can I do? thanks, Adam <Hi Adam.  Adam here.  There are many reasons why this might be the case.  Please write back with some information about your lighting, water movement, filtration and water chemistry (Nitrate, pH, Calcium, Alkalinity).  Please also list the other fish and corals that you have.  Best Regards.  AdamC>
<<Anthony here... as Adam C has stated... there are many possible reasons for this, and it is not even an indicator of good or better health. Still... if you want to finesse this, know that inadequate water flow (not enough or not enough of the right kind... as with powerheads/laminar outlets... yuck). Nutrient levels are an issue too... some folks cheat by adding a tablespoon of sugar to the tank on occasion. Not a great long term habit, but add one spoonful and see what happens (this is safe in one shot). It speaks to how some sugared supplements trick you into believing they are effective. Anthony>

Acros only open at night 11/26/04
Hi all,
<cheers>
I have read every thing I could find on your site and I still can't get the answer I am looking for. First let me tell you about my setup. My 55 gallon tank has been running for 18 months with DSB, remora skimmer, 15X circulation, PC 260 watts (lamps 5mths old), mech. filter for charcoal and lots of live rock.
My measurements are 1.024,0,0,0, ph 8.35, pH .05, temp 80, cal 400 and alk 8.5. All test are double checked by my LFS once a month. I have a clown, flame angel and a hawk fish, all since the beginning. My corals are lots of mushrooms, zoos, one Xenia and on the top Acros, pink birdsnest, trumpet, plate and a brain coral.  All corals have a good separation. I feed the fish a large variety of frozen foods. The corals I feed a cocktail of Phycopure and Cyclop-eeze or DT's and for the larger coral I feed bits of fish food like Mysis. On Sunday I stir the top of the sand bed, clean my skimmer, 10% water change and run test. I have no algae problems, lots of coralline algae and everything is growing and happy.  In fact, at least once a month, I have to pull some of the corals and give them away. When I first got the Acros, they opened during the day for 2 weeks but for the past 4 months the Acros open only at night.  I see lots of them in other tanks that are open during the day.  I have tried to entice them with food during the day but it does not work.  
<hmmm.. since they do not feed organically very well/heavily... this is not a principal influence (feeding). More likely water flow is the culprit. And the change from behaviors on arrival is simply their acclimation (or even suffrage if the flow is too low or way too high)>
However, they eat well at night.  I have to believe that my Acros are getting all they need.  I know that I could use more light but they are at the same level as the birdsnest and if it is growing, I don't think that light is the problem.
<agreed>
Do you have any ideas?
<lots... the Pittsburgh Steelers should try to run Jerome Bettis again this week and give Duce at least another week to rest>
If you think it is the lights are VHO ok?  
<very fine lights and good color. I like the URI brand best. Change any brand VHO by 10 months>
MH just put out too much heat.
<Ahhh... actually not my friend. It really is a misinformation. VHOs as close to the water as they need to be if effective (less than 3") are also hot. And either lamp style can easily be cooled with a single muffin fan (9 watts) and a well-designed fixture. MH are a better value by far in the long run considering lamp life, trueness of color, intensity (bang for your buck on light produced per watt), etc>
PS I owe you all a big thanks.  I have saved a lot of money.  Fan vs. chiller in the summer, proper equipment selection, etc.
Thanks
<very welcome my friend. With kind regards. Anthony>

Acroporas turning brown
Hi WWM! <Hi Jen, MacL here with you tonight.>
I know you all are so busy these days, I have tried to research this on my own and can't really find a lot of info on Acroporas turning brown.  I have asked several online dealers and the LFS, but I get very conflicting information. <I can tell you right now that's because multiple things can turn the corals brown.> I have been told I didn't have enough lighting (when I had 2 X 150W HQI MH), and upgraded to 2 X 250W HQI MH, and now have been told I have too much lighting. <Did you acclimate the corals to the stronger lighting? By acclimate I mean did you give them time to grow accustomed to the stronger lighting by putting them on for less hours or perhaps higher above the tank?> I don't know how much info you need to be able to tell me why this is happening, but here goes. . .
80 gallon tank, setup three years ago.  100 lbs. of LR, 60-80 lbs. LS, Lighting: 2X 250 W HQI MH 14k, 2X 96 W PC Actinics, mounted 10" off top of tank.  Aqua C Remora Pro (upgraded skimmer 6 months ago), 4 Maxi-jet powerheads, approx 920 gph.
Livestock: 1 blue tang, 1 royal Gramma, 1 lawnmower blenny, 1 six line wrasse, 1 citron goby, 3 blue Chromis, 1 cinnamon clown, 15-20 Turbo snails, 10 Nassarius snails, 20 Astrea snails, 25 various dwarf hermit crabs, 2 blue tuxedo urchins, 2 Mithrax crabs, 5-10 Cerith snails, 2 brain corals, 1 Favites, 1 Blastomussa, 1 Montipora (also turned brown), 1 Acropora, 1 yellow Porites.  The Acropora and the Montipora are both near the top of the tank, top 10".  
Water Parameters:  PH 8.3 1:30pm, Temp 80, Amm 0, Trites 0, Trates 0, Phosphates 0, Alk 8.4-9.2 DKH, Calc 375, SG 1.025.
I use RO/DI water for top off and water changes.  I top off with one gallon every night.  I change about 5 gallons per week.  I use Kalkwasser,  turbo calcium, and Warner Marine's two part A and B.  I also started adding this week Kent's Essential Elements (which I was told I should be adding every week).  <Your levels look great but let me ask? are you having any ph fluctuation? Also, how long after you got the corals did they turn color? How long had you had them? Do you have any idea if they are wild corals? Often wild corals turn colors but will often regain color after they adjust to the tank.  Wild Acroporas will often change as part of their adjustment. See what I mean by it could be a lot of things?>
Please let me know what you think may be causing these corals to turn brown.  I have also read "high nutrients" can cause this browning. What nutrients?? <Phosphates can be a problem but generally high nutrients are what they call the "dirty tank" which is often lots of algae, plankton, etc.>  Where are they coming from?  How can I test for them?  If I was overfeeding wouldn't I see a rise in nitrates and phosphates?  I am just completely confused and my head is spinning with what everybody has been telling me, please set me straight. <No worries Jen, I think the most confusing part is  that Acroporas can change because of many things and the biggest thing is just to go down the list one thing at a time to try to isolate what did it. Don't worry we can help you.>  Thank You,  Jen Marshall    
 

 

 

 


 

 

 

 

 

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